1. Field of the Invention
The present invention relates generally to polyurea elastomers and, more specifically, to spray and reaction injection molded polyurea elastomers which exhibit reduced moisture vapor transmission.
2. Description of Background Art
Elastomer systems are commonly recognized as, among other things, coating materials, with spray polyurea elastomer systems being particularly useful when employed in this capacity; rooftops and floorings are particularly well suited substrates. In addition to coating applications, spray polyurea elastomers are also employed in other open mold spraying applications for part production. Polyurea elastomers are also used for part production in closed mold applications, such as reaction injection molding (RIM) and reinforced reaction injection molding (RRIM).
There are many applications where it is desirable to employ a coating material which will resist the transmission of water. For example, substrates like steel and concrete will experience less corrosion when coated by a spray polyurea elastomer with a reduced moisture vapor transmission rate; landfills can be lined with a polyurea elastomer barrier film exhibiting a reduced moisture vapor transmission rate to reduce or prevent moisture penetration which can cause leaching of materials from the landfill; and environments which require low humidity can be lined with such a polyurea elastomer. In these coating applications, a prime consideration is the rate at which the spray polyurea elastomer coating will transmit moisture vapor. A polyurea elastomer with a higher moisture vapor transmission rate will not provide the corrosion protection or prevention of leaching which is required by these applications. Such a failure can not be tolerated in an environmentally sensitive application.
In accordance with the present invention the moisture vapor transmission of a polyurea elastomer is substantially reduced, thereby overcoming those shortcomings identified above.